Reciprocating vane pumps have been know for many years. They come in a number of varieties, in which either the vanes reciprocate vertically, or reciprocate radially in the space intermediate eccentrically disposed cylinders, or between non-cylindrical surfaces disposed to define lobate surfaces, such as might be generated from hypocyclic and epicyclic curves. The common factor in all cases is the use of a variable geometry chamber formed between an adjacent pair of vanes, a pair of opposed end walls swept by the vanes, and a pair of opposed inner and outer walls, either or both of which may also be swept by the vanes. The more recent scroll compressors are able to achieve this variable geometry chamber with only four walls, rather than six, but nonetheless operate on the same general principle. In general the chamber volume varies to draw in fluid in one phase of revolution, then is progressively reduced to compress the fluid and expel it through one or more exhaust ports. In all cases it is the mechanical movement of the chamber wall which actually compresses the fluid.
An example of this kind of device is shown in U.S. Pat. No. 2,020,611 granted to Knapp. Knapp described a vertically, or longitudinally reciprocating vane compressor in which a series of vanes 19 reciprocate between two vertically, or longitudinally, undulating camming surfaces 34 and 35. Working fluid is drawn in, and in turn expelled, through ports 35 and 36, and, in particular, via ports 37a and 38 located in the camming surfaces themselves.
U.S. Pat. No. 4,653,603 to DuFrene also shows a vertically reciprocating vane compressor for use with hydraulic fluid that may work in either clockwise or counterclockwise direction and is provided with a steering return-to-neutral system.
Examples of the eccentric cylinder of vane compressors are shown in U.S. Pat. No. 2,303,589 and U.S. Pat. No. 2,280,271, both to Sullivan. Another patent granted to Sullivan, U.S. Pat. No. 2,280,272 illustrates two variations of arcuate lobe vane compressors, particularly as illustrated in FIGS. 2 and 3 thereof.
An interesting variation on the vertically reciprocating vane compressor is shown in U.S. Pat. No. 4,439,117 to Bunger in which the phase angle, and hence volumetric displacement of the pump can be altered. U.S. Pat. No. 4,566,869 to Pandeya et al. teaches a reversible arcuate lobe multivane vane compressor, with the known radially reciprocating vanes. U.S. Pat. No. 5,064,362 to Hansen shows another variation of pump with radially reciprocating vanes operating between a cylindrical rotor and elliptical stator. In all of these cases compression of the working fluid is achieved by reducing the size of the chambers into which the working fluid is periodically drawn and whence it is subsequently expelled.